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Today's best, commercially- available concentrating solar power (CSP) technologies
can harness the sun's energy to heat working fluids to 565 °C. While these plants
have driven significant reductions in the cost of CSP-generated electricity, CSP costs
must continue to decline to keep pace with PV and other energy sources. A new U.S.
Department of Energy research program aims to develop a commercial-scale, high-temperature
CSP system with working temperatures of at least 700 °C, while also incorporating
thermal energy storage.

Of the $72 million awarded by DOE for this program, NREL has received $7 million as
one of three teams that are each exploring a different CSP technology pathway. The
NREL team, led by CSP researcher Craig Turchi, will develop the next generation of
liquid-phase CSP technology by advancing the current molten-salt power tower technologies
to higher temperatures and efficiencies. The project will design, develop, and test
a two-megawatt thermal system. If selected for the next phase of the program, the
NREL team will receive an additional $25 million over the subsequent three years to
develop a test facility.

In addition to this liquid-phase technology pathway research, NREL will also be supporting
research on the two other technology pathways—a gas-phase plant and particle plant—and
will be involved in several other supporting research projects.

Over the years, NREL researchers have studied hundreds of thousands of samples in
their quest to find useful inorganic materials for advanced energy applications, such
as thin-film solar cells. Yet data on only a tiny fraction—the most promising or interesting
materials—was ever published. Now, the newly launched High Throughput Experimental
Materials (HTEM) Database offers information on more than 140,000 sample entries collected
by NREL scientists. HTEM entries provide details on the structural, chemical, and
optoelectronic properties of the materials and their synthesis conditions.

Much of the data in HTEM was gathered through NREL's combinatorial research, which
produces materials with varied properties to maximize the output of new data. For
example, a thin-film sample measuring 2 inches on each side can have 100 data points.
How so? Because such a sample "library" is intentionally made with gradients in chemical
composition, synthesis temperature, or film thickness. "Doing such combinatorial research
systematically over many years, for different projects with different goals is what
allowed us to create this database," said Andriy Zakutayev, a scientist who worked
on the database. About half of the total dataset is already available online, where results can be searched by element, then visualized.

In a new collaborative research initiative, NREL is bringing together teams from cities,
states, companies, and non-profits across the country to understand how solar can
solve challenges related to modernizing the U.S. electric grid. Round One of the Solar
Energy Innovation Network comprises nine teams, each consisting of several different
stakeholders who all work within a similar technology or geographic area.

Teams implementing pilot projects are paired with analytical support from a broad
set of technical experts, such as NREL. The goal is for this innovation network to
develop novel applications of solar energy and other distributed energy technologies.
To make them ready for widespread adoption, these applications will be rigorously
demonstrated and validated in real-world laboratories. The application process for
Round 2 for the Innovation Network will begin in July 2018.

The Institute of Electrical and Electronics Engineers (IEEE) has just published the
full revision of IEEE 1547, which establishes uniform requirements for interconnection of distributed energy
resources (DERs), such as solar photovoltaics, with the electric power system. "This
full revision will help to accelerate modernization of our electric power systems
infrastructure by enabling the use of modern DER technologies, such as grid-supportive
inverters," said David Narang, NREL principal engineer and chair of the IEEE 1547
Revision Working Group. "This builds on the foundation for integrating clean renewable
energy technologies as well as other distributed generation and energy storage technologies.

Early developments of the standard were largely influenced by the pioneering efforts
NREL engineers Dick DeBlasio, Ben Kroposki, and Tom Basso, and NREL has continued
to play a major role in developing the standard. For example, NREL engineers Andy
Hoke and Mike Coddington have been leading sub-groups related to IEEE 1547, for secondary
grid networks, and the sister standard, IEEE 1547.1, which defines the testing procedures
for conformance to IEEE 1457-2018.

To some, a modern energy system is a complex beast, composed of millions of interdependent
energy resources. So, providing a comprehensive simulation can be a nightmarish endeavor.
Many software models can simulate parts of such a system, with no off-the-shelf solution
able to link all these models to reconstruct a complete system. But now, a new NREL-developed
software package—the Hierarchical Engine for Large-scale Infrastructure Co-Simulation
(HELICS)—provides just what is needed: a high-performance framework that links models
for both the cyber and physical domains of energy systems.

HELICS uses co-simulation to combine off-the-shelf simulation tools to act as a single
unified model, exchanging data at each time step. This makes simulation possible for
complex power systems, end-use, and communication/control interactions. And it does
this at scales ranging from smart homes up to system-wide, transmission-distribution
systems as large as the Western Interconnection. Two NREL researchers, Bryan Palmintier
and Dheepak Krishnamurthy, are the masterminds behind the newly debuted software.
Their effort, as part of the Grid Modernization Laboratory Consortium, combines the
collective experience of multiple national laboratories.

To date, existing rooftop solar adoption in the U.S. has been mostly concentrated
in middle- and upper-income households. However, a new NREL analysis has found that
the rooftops of low and moderate-income housing represent 42 percent of all rooftop
technical potential in the U.S. residential sector.

"We designed the study and associated tool to provide quality, objective data to help
inform the decisions of all key stakeholders," said report author Benjamin Sigrin.
"The findings can help communities make informed decisions that best meet their needs
as they address long-term solar adoption targets across demographic categories and
building type."